Additional notes on epoxy resins to help you get
the structures down correctly

This product, where n = 10 or so forms one of the components
of the epoxy resin. Not each of the reactions used to form it
involve nucleophilic attack on an oxirane coupled with
intramolecular formation of an oxirane

The second liquid used contains a polyamine. The amine groups
in this second liquid react with the terminal oxirane groups
again involving a nucleophilic attack on the oxirane (SN2). As
the amines are polyamines the reactions join together the
oxirane containing compounds to form a highly cross-linked
polymer. The reaction is shown on the next page.